Idle issue 2.7 RS replica

[NSD]

Hi I have a Carrera 2.7 RS replica with and idle issue.

The original car is a 68 912 converted in the 1990s with parts mostly from Autofarm by an ex Porsche mechanic. It has a 2.7 S engine fitted.

The issue is the car idles steadily at 1200 rpm on start but after driving when the clutch is depressed the revs will not go below 2200 rpm unless the car is left in gear and the brake applied to force the rpms lower, as soon as 2200 rpm is reached the idle returns to 1200 again but the cycle just repeats as soon as it is driven above 2200 rpm.

Any help would be much appreciated.

Thank you

NSD

[hot66]

a 1974 onwards 2.7 S engine with CIS ?

[misteralz]

Sounds like the ISV. Take it off and plonk it in an ice cream tub full of brake cleaner overnight. Bonus brave points if you hook it up to a car battery.

[NSD]

Yes its a CIS system

[PeterK]

When I had similar it was a sticky throttle linkage. Turned out to be where a plastic ‘bearing sleeve’ had moved and the (front to back in the tunnel) throttle rod was getting caught up.